Yi, Shuang-Xi 2013 任意幂律形式的环境下的正反激波

主要内容:
一般动力学和辐射。发现很多暴的环境指数（n~r^-k）中的k不是0或者2，而是1附近。

精彩摘抄:

文章信息:

· Find Similar Abstracts (with default settings below)

· Electronic Refereed Journal Article (HTML)

· Full Refereed Journal Article (PDF/Postscript)

· arXiv e-print (arXiv:1308.6095)

· References in the article

· Citations to the Article (1) (Citation History)

· Refereed Citations to the Article

· SIMBAD Objects (19)

· Also-Read Articles (Reads History)

·

· Translate This Page

Title:		Early Afterglows of Gamma-Ray Bursts in a Stratified Medium with a Power-law Density Distribution
Authors:		Yi, Shuang-Xi; Wu, Xue-Feng; Dai, Zi-Gao
Affiliation:		AA(School of Astronomy and Space Science, Nanjing University, Nanjing 210093, China ; Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, China; dzg@nju.edu.cn), AB(Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China ; Chinese Center for Antarctic Astronomy, Chinese Academy of Sciences, Nanjing 210008, China ; Joint Center for Particle Nuclear Physics and Cosmology of Purple Mountain Observatory-Nanjing University, Chinese Academy of Sciences, Nanjing 210008, China), AC(School of Astronomy and Space Science, Nanjing University, Nanjing 210093, China ; Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, China)
Publication:		The Astrophysical Journal, Volume 776, Issue 2, article id. 120, 15 pp. (2013). (ApJ Homepage)
Publication Date:		10/2013
Origin:		IOP
Astronomy Keywords:		gamma-ray burst: general, radiation mechanisms: non-thermal
DOI:		10.1088/0004-637X/776/2/120
Bibliographic Code:		2013ApJ...776..120Y

Abstract

A long-duration gamma-ray burst (GRB) has been widely thought to arise from the collapse of a massive star, and it has been suggested that its ambient medium is a homogenous interstellar medium (ISM) or a stellar wind. There are two shocks when an ultra-relativistic fireball that has been ejected during the prompt gamma-ray emission phase sweeps up the circumburst medium: a reverse shock that propagates into the fireball, and a forward shock that propagates into the ambient medium. In this paper, we investigate the temporal evolution of the dynamics and emission of these two shocks in an environment with a general density distribution of nvpropR ^–k (where R is the radius) by considering thick-shell and thin-shell cases. A GRB afterglow with one smooth onset peak at early times is understood to result from such external shocks. Thus, we can determine the medium density distribution by fitting the onset peak appearing in the light curve of an early optical afterglow. We apply our model to 19 GRBs and find that their k values are in the range of 0.4-1.4, with a typical value of k ~ 1, implying that this environment is neither a homogenous ISM with k = 0 nor a typical stellar wind with k = 2. This shows that the progenitors of these GRBs might have undergone a new mass-loss evolution.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)